N-acyl-b-lactam derivative, macromolecular compound, and photoresist composition

ABSTRACT

Disclosed are an N-acyl-β-lactam derivative represented by the following general formula, from which a photoresist composition capable of controlling an acid diffusion length to be short is obtained; a polymer obtained by polymerizing the N-acyl-β-lactam derivative represented by the following general formula as one of starting materials; and a photoresist composition containing the polymer. 
     
       
         
         
             
             
         
       
     
     In the formula, R 1  represents a hydrogen atom, a methyl group, or a trifluoromethyl group; W represents an alkylene group or a cycloalkylene group; n represents 0 or 1; and each of R 2 , R 3 , R 4 , and R 5  independently represents a hydrogen atom, an alkyl group, a cyclic hydrocarbon group, or an acyloxy group, provided that 1) R 2  and R 3 , or R 4  and R 5 , may be connected to each other to form a substituted or unsubstituted ring which may have an oxygen atom at an arbitrary position, 2) R 3  and R 4  may be connected to each other to form a substituted or unsubstituted ring which may have an oxygen atom at an arbitrary position, and 3) all of R 2 , R 3 , R 4 , and R 5  are not a hydrogen atom at the same time.

TECHNICAL FIELD

The present invention relates to an N-acyl-β-lactam derivative, apolymer obtained by polymerizing at least the N-acyl-β-lactam derivativeas one of starting materials, and a photoresist composition having ashort acid diffusion length, in which a line width roughness (LWR) isimproved and from which a resist pattern having a high resolution isformed.

BACKGROUND ART

In recent years, in the field of manufacture of electronic devicesrepresented by the manufacture of integrated circuit devices,requirements for high integration of devices are increasing, and it isknown that the structure of a polymer in a photoresist compositioninfluences the formation of a fine pattern.

In the photoresist composition, lithography properties such assensitivity to an exposure light source, resolution capable of forming apattern having fine dimensions, and the like are required, andtherefore, Chemically amplified photoresist compositions composed of anacid dissociable functional group-containing polymer and a compoundcapable of generating an acid upon irradiation with radiations(hereinafter referred to as “exposure”) (the latter compound will behereinafter referred to as “photo acid generator”) is used. The aciddissociable functional group-containing polymer is based on a structurein which a part of an alkali easily soluble site of an alkali solublepolymer is protected by an appropriate acid dissociable functionalgroup, and the selection of such an acid dissociable functional group isvery important in view of regulating a function as a photoresistcomposition.

As the already-known acid dissociable functional group-containingpolymer which is incorporated into the photoresist composition, forexample, there are known polymers obtained by polymerizing a materialcontaining an adamantyl group-containing acrylic ester (see PatentDocument 1); polymers having, as a constituent unit, a lactoneskeleton-containing acrylic ester introduced thereinto (see PatentDocument 2); polymers having a norbornane lactone skeleton-containingconstituent unit (see Patent Documents 3 to 5); and the like.

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: JP-A-9-73173-   Patent Document 2: JP-A-9-90637-   Patent Document 3: JP-A-2000-26446-   Patent Document 4: JP-A-2001-188346-   Patent Document 5: JP-A-2008-31298

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

One of important problems of the lithography technology of recent yearsis to minimize a line width fluctuation of a formed pattern, which iscalled a line width roughness (LWR). However, in photoresistcompositions containing each of the polymers disclosed in PatentDocuments 1 to 5, the LWR cannot be sufficiently reduced, and therefore,there is room for more improvement.

Then, an object of the present invention is to provide a novel compoundcapable of obtaining a photoresist composition from which ahigh-resolution resist pattern having improved LWR is formed, a polymerobtained by polymerizing at least the novel compound as one of startingmaterials, and a photoresist composition containing the polymer.

Means for Solving the Problems

In order to solve the foregoing problems, the present inventors madeextensive and intensive investigations. As a result, it has been foundthat by using a photoresist composition using a compound capable ofcontrolling an acid diffusion length to be short, the LWR can beimproved and that a resist pattern having a high resolution is formed.

That is, the present invention provides the following [1] to [6].

[1] An N-acyl-β-lactam derivative represented by the following generalformula (1):

(in the formula, R¹ represents a hydrogen atom, a methyl group, or atrifluoromethyl group; W represents an alkylene group having a carbonnumber of from 1 to 10 or a cycloalkylene group having a carbon numberof from 4 to 10; n represents 0 or 1; and each of R², R³, R⁴, and R⁵independently represents a hydrogen atom, an alkyl group having a carbonnumber of from 1 to 5, a cyclic hydrocarbon group having a carbon numberof from 3 to 10, or an acyloxy group having a carbon number of from 2 to6, provided that

1) R² and R³, or R⁴ and R⁵, may be connected to each other to form asubstituted or unsubstituted ring having a ring forming atom number offrom 3 to 10, which may have an oxygen atom at an arbitrary position,

2) R³ and R⁴ may be connected to each other to form a substituted orunsubstituted ring having a ring forming atom number of from 4 to 10,which may have an oxygen atom at an arbitrary position, and

3) all of R², R³, R⁴, and R⁵ are not a hydrogen atom at the same time.)

[2] The N-acyl-β-lactam derivative as set forth above in [1], which isrepresented by the following general formula (1-1):

(in the formula (1-1), R¹ represents a hydrogen atom, a methyl group, ora trifluoromethyl group; each of R² and R⁵ independently represents ahydrogen atom or an alkyl group having a carbon number of from 1 to 5; Wrepresents an alkylene group having a carbon number of from 1 to 10 or acycloalkylene group having a carbon number of from 4 to 10; n represents0 or 1; and Z¹ represents a ring formed together with the two carbonatoms on the β-lactam, with a number of atoms forming the ring beingfrom 3 to 10.)[3] The N-acyl-β-lactam derivative as set forth above in [1], which isrepresented by the following general formula (1-2):

(in the formula (1-2), R¹ represents a hydrogen atom, a methyl group, ora trifluoromethyl group; each of R⁴ and R⁵ independently represents ahydrogen atom or an alkyl group having a carbon number of from 1 to 5; Wrepresents an alkylene group having a carbon number of from 1 to 10 or acycloalkylene group having a carbon number of from 4 to 10; n represents0 or 1; and Z² represents an aliphatic ring formed together with thecarbon atom on the β-lactam, with a carbon number forming the aliphaticring being from 3 to 10.)[4] The N-acyl-β-lactam derivative as set forth above in [1], which isrepresented by the following general formula (1-3):

(in the formula (1-3), R¹ represents a hydrogen atom, a methyl group, ora trifluoromethyl group; each of R⁴ and R⁵ independently represents ahydrogen atom or an alkyl group having a carbon number of from 1 to 5; Wrepresents an alkylene group having a carbon number of from 1 to 10 or acycloalkylene group having a carbon number of from 4 to 10; n represents0 or 1; and R^(A) represents an alkyl group having a carbon number offrom 1 to 5 or a cyclic hydrocarbon group having a carbon number of from3 to 10.)[5] A polymer obtained by polymerizing the N-acyl-β-lactam derivative asset forth above in any one of [1] to [4].[6] A photoresist composition containing the polymer as set forth abovein [5], a photo acid generator, and a solvent.

EFFECTS OF THE INVENTION

According to the photoresist composition of the present invention, bycontrolling the acid diffusion length to be short, the LWR can beimproved, and a resist pattern having a high resolution is formed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing a correlation between a post-exposure bake(PEB) temperature of each of photoresist films formed from PhotoresistCompositions A to C obtained in Examples 11 to 13 and PhotoresistComposition F obtained in Comparative Example 1 and an exposure dose oflight irradiated until the photoresist film has caused film dissolution.

FIG. 2 is a graph showing a correlation between a post-exposure bake(PEB) temperature of a photoresist film formed from PhotoresistComposition D obtained in Example 14 and Photoresist Composition Fobtained in Comparative Example 1 and an exposure dose of lightirradiated until the photoresist film has caused film dissolution.

FIG. 3 is a graph showing a correlation between a post-exposure bake(PEB) temperature of a photoresist film formed from PhotoresistComposition E obtained in Example 15 and Photoresist Composition Fobtained in Comparative Example 1 and an exposure dose of lightirradiated until the photoresist film has caused film dissolution.

MODES FOR CARRYING OUT THE INVENTION N-Acyl-β-lactam Derivative

In order to obtain a photoresist composition which controls an aciddiffusion length to be short, an N-acyl-β-lactam derivative representedby the following general formula (1) (hereinafter referred to as“N-acyl-β-lactam derivative (1)”) is useful.

In the foregoing general formula (1), R¹ represents a hydrogen atom, amethyl group, or a trifluoromethyl group.

W represents an alkylene group having a carbon number of from 1 to 10 ora cycloalkylene group having a carbon number of from 4 to 10.

Examples of the alkylene group having a carbon number of from 1 to 10,which W represents, include a methylene group, an ethane-1,1-diyl group,an ethane-1,2-diyl group, a propane-1,1-diyl group, a propane-1,2-diylgroup, a propane-1,3-diyl group, a pentane-1,5-diyl group, ahexane-1,1-diyl group, and so on. Of these, from the viewpoint ofobtaining a photoresist composition whose acid diffusion length iscontrolled to be short, a methylene group and an ethane-1,1-diyl groupare preferable. Also, examples of the cycloalkylene group having acarbon number of from 4 to 10, which W represents, include acyclohexane-1,2-diyl group, a cyclohexane-1,4-diyl group, acyclodecane-1,5-diyl group, and so on.

n represents 0 or 1, and from the viewpoint of obtaining a photoresistcomposition whose acid diffusion length is controlled to be short, n ispreferably 0.

In the foregoing general formula (I), each of R², R³, R⁴, and R⁵independently represents a hydrogen atom, an alkyl group having a carbonnumber of from 1 to 5, a cyclic hydrocarbon group having a carbon numberof from 3 to 10, or an acyloxy group, provided that

1) R² and R³, or R⁴ and R⁵, may be connected to each other to form asubstituted or unsubstituted ring having a ring forming atom number offrom 3 to 10, which may have an oxygen atom at an arbitrary position,

2) R³ and R⁴ may be connected to each other to form a substituted orunsubstituted ring having a ring forming atom number of from 4 to 10,which may have an oxygen atom at an arbitrary position, and

3) all of R², R³, R⁴, and R⁵ are not a hydrogen atom at the same time.

Examples of the alkyl group having a carbon number of from 1 to 5, whicheach of R², R³, R⁴, and R⁵ independently represents, include a methylgroup, an ethyl group, an n-propyl group, an isopropyl group, an n-butylgroup, an isobutyl group, a t-butyl group, an n-pentyl group, anisopentyl group, an s-pentyl group, a t-pentyl group, and so on.

Examples of the cyclic hydrocarbon group having a carbon number of from3 to 10, which each of R², R³, R⁴, and R⁵ independently represents,include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, acyclohexyl group, a 1-adamantyl group, a bicyclo[2.2.1]heptan-1-ylgroup, and so on.

Examples of the acyloxy group which each of R², R³, R⁴, and R⁵independently represents include an acetyloxy group, a propionyloxygroup, a butyryloxy group, and so on.

Also, examples of the ring having a ring forming atom number of from 3to 10, which R² and R³, or R⁴ and R⁵, may be connected to each other toform and which may have an oxygen atom at an arbitrary position, includea cyclopropane ring, a cyclobutane ring, a cyclopentane ring, acyclohexane ring, a cycloheptane ring, a camphane ring, a norbornanering, an adamantane ring, a tetrahydrofuran ring, a tetrahydropyranring, and so on. The ring may have a substituent, and examples of thesubstituent include an acetyloxy group, a propionyloxy group, a cyanogroup, a nitro group, and so on.

Examples of the ring having a ring forming atom number of from 4 to 10,which R³ and R⁴ may be connected to each other to form and which mayhave an oxygen atom at an arbitrary position, include a cyclobutanering, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, acyclooctane ring, a bicyclo[2.2.1]heptane ring, atricyclo[5.2.1.0^(2.6)]decane ring, a tetrahydrofuran ring, atetrahydropyran ring, and so on. The ring may have a substituent, andexamples of the substituent include an acetyloxy group, a propionyloxygroup, a cyano group, a nitro group, and so on.

Among those of the foregoing general formula (I), from the viewpoint ofobtaining a photoresist composition whose acid diffusion length iscontrolled to be short, N-acyl-β-lactam derivatives represented by thefollowing general formulae (1-1) to (1-3) are preferable.

In the foregoing general formula (1-1), R¹ represents a hydrogen atom, amethyl group, or a trifluoromethyl group. Each of R² and R⁵independently represents a hydrogen atom or an alkyl group having acarbon number of from 1 to 5. W represents an alkylene group having acarbon number of from 1 to 10 or a cycloalkylene group having a carbonnumber of from 4 to 10. n represents 0 or 1. Specific examples of thesegroups are the same groups as those described regarding R¹, R², R⁵, W,and n in the general formula (1), and preferred examples thereof arealso the same.

Also, Z¹ represents a ring formed together with the two carbon atoms onthe β-lactam, with a number of atoms forming the ring being from 3 to10. Examples of the ring include an aliphatic ring and an ether ring inwhich an arbitrary carbon atom of the aliphatic ring is converted intoan oxygen atom. Examples of the aliphatic ring include a cyclopropanering, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, acycloheptane ring, a cyclooctane ring, a bicyclo[2.2.1]heptane ring, atricyclo[5.2.1.0^(2.6)]decane ring, and so on. Also, examples of theether ring include a tetrahydrofuran ring, a tetrahydropyran ring, andso on. The ring structure may have a substituent, and examples of thesubstituent include an alkyl group having a carbon number of from 1 to10 (preferably from 1 to 5), such as a methyl group, an ethyl group, andthe like; an acyloxy group having a carbon number of from 2 to 10(preferably from 2 to 6), such as an acetyloxy group, a propionyloxygroup, and the like; a cyano group; a nitro group; and so on.

From the viewpoint of obtaining a photoresist composition whose aciddiffusion length is controlled to be short, Z¹ is preferably acyclopentane ring or a tricyclo[5.2.1.0^(2.6)]decane ring.

In the foregoing general formula (1-2), R¹ represents a hydrogen atom, amethyl group, or a trifluoromethyl group. Each of R⁴ and R⁵independently represents a hydrogen atom or an alkyl group having acarbon number of from 1 to 5. W represents an alkylene group having acarbon number of from 1 to 10 or a cycloalkylene group having a carbonnumber of from 4 to 10. n represents 0 or 1. Specific examples of thesegroups are the same groups as those described regarding R¹, R⁴, R⁵, W,and n in the general formula (1), and preferred examples thereof arealso the same.

Also, Z² represents an aliphatic ring formed together with the carbonatom on the β-lactam, with a carbon number forming the aliphatic ringbeing from 3 to 10. Examples of the aliphatic ring include acyclopropane ring, a cyclobutane ring, a cyclopentane ring, acyclohexane ring, a cycloheptane ring, a cyclooctane ring, abicyclo[2.2.1]heptane ring, a tricyclo[5.2.1.0^(2.6)]decane ring, anadamantane ring, and so on. The ring structure may have a substituent,and examples of the substituent include an alkyl group having a carbonnumber of from 1 to 10 (preferably from 1 to 5), such as a methyl group,an ethyl group, and the like; an acyloxy group having a carbon number offrom 2 to 10 (preferably from 2 to 6), such as an acetyloxy group, apropionyloxy group, and the like; a cyano group; a nitro group; and soon.

In the foregoing general formula (1-3), R¹ represents a hydrogen atom, amethyl group, or a trifluoromethyl group. Each of R⁴ and R⁵independently represents a hydrogen atom or an alkyl group having acarbon number of from 1 to 5. W represents an alkylene group having acarbon number of from 1 to 10 or a cycloalkylene group having a carbonnumber of from 4 to 10. n represents 0 or 1. Specific examples of thesegroups are the same groups as those described regarding R¹, R⁴, R⁵, W,and n in the general formula (1), and preferred examples thereof arealso the same.

Also, R^(A) represents an alkyl group having a carbon number of from 1to 5 or a cyclic hydrocarbon group having a carbon number of from 3 to10. Examples of the alkyl group having a carbon number of from 1 to 5include a methyl group, an ethyl group, an n-propyl group, an isopropylgroup, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentylgroup, an isopentyl group, an s-pentyl group, a t-pentyl group, and soon. Examples of the cyclic hydrocarbon group having a carbon number offrom 3 to 10 include a cyclic aliphatic hydrocarbon group such as acyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexylgroup, an adamantyl group, a bicyclo[2.2.1]heptan-1-yl group, atricyclo[5.2.1.0^(2.6)]decan-8-yl group, and the like, and a cyclichydrocarbon group having a carbon number of from 4 to 6 is preferable.Incidentally, from the viewpoint of obtaining a photoresist compositionwhose acid diffusion length is controlled to be short, R^(A) ispreferably a methyl group.

Manufacturing method of N-acyl-β-lactam derivative (1)

Though a manufacturing method of the N-acyl-β-lactam derivative (1) isnot particularly limited, for example, the N-acyl-β-lactam derivative(1) can be manufactured by the following step.

The N-acyl-β-lactam derivative (1) wherein n is 0 can be manufactured bythe following polymerizable group introducing step-A.

In the polymerizable group introducing step-A, the foregoingN-hydro-β-lactam derivative (2) is allowed to react with a compoundrepresented by a formula: CH₂═CR¹COX¹ (in the formula, R¹ is the same asdefined above; and X¹ represents a chlorine atom, a bromine atom, or aniodine atom), a formula: (CH₂═CR¹CO)₂O (in the formula, R¹ is the sameas defined above), a formula: CH₂═CR¹COOC(═O)R⁶ (in the formula, R¹ isthe same as defined above; and R⁶ represents a t-butyl group or a2,4,6-trichlorophenyl group), or a formula: CH₂═CR¹COOSO₂R⁷ (in theformula, R¹ is the same as defined above; and R⁷ represents a methylgroup or a p-tolyl group) (such a compound will be hereinafter referredto as “polymerizable group introducing agent A”) in the presence of abasic substance.

The N-acyl-β-lactam derivative (1) wherein n is 1 can be manufactured bythe following polymerizable group introducing step-B. Incidentally, thepolymerizable group introducing step-B is composed of polymerizablegroup introducing steps-B1 and B2.

In the polymerizable group introducing step-B1, the foregoingN-hydro-β-lactam derivative (2) is allowed to react with a compoundrepresented by a formula: X²-W-COX³ (in the formula, W is the same asdefined above; and each of X² and X³ independently represents a chlorineatom, a bromine atom, or an iodine atom), a formula: (X²-W-CO)₂O (in theformula, X² and W are the same as defined above), a formula:X²-W-COOC(═O)R⁸ (in the formula, X² and W are the same as defined above;and R⁸ represents a t-butyl group or a 2,4,6-trichlorophenyl group), ora formula: X²-W-COOSO₂R⁹ (in the formula, X² and W are the same asdefined above; and R⁹ represents a methyl group or a p-tolyl group)(such a compound will be hereinafter referred to as “connecting groupintroducing agent B1”) in the presence of a basic substance.

Subsequently, as the polymerizable group introducing step-B2, theresultant is allowed to react with a compound represented by a formula:CH₂═CR¹COOM (in the formula, R¹ is the same as defined above; and Mrepresents a sodium atom or a potassium atom) (this compound will behereinafter referred to as “polymerizable group introducing agent B2”).

The polymerizable group introducing step-A and the polymerizable groupintroducing step-B are hereunder described in succession.

(Polymerizable Group Introducing Step-A)

Among the polymerizable group introducing agents A which are used in thepolymerizable group introducing step-A, examples of the compoundrepresented by the formula: CH₂═CR¹COX¹ include acryloyl chloride,methacryloyl chloride, and the like. Examples of the compoundrepresented by the formula: (CH₂═CR¹CO)₂O include acrylic anhydride,methacrylic anhydride, and the like. Examples of the compoundrepresented by the formula: CH₂═CR¹COOC(═O)R⁶ include acrylic pivalicanhydride, acrylic 2,4,6-trichlorobenzoic anhydride, methacrylic pivalicanhydride, methacrylic 2,4,6-trichlorobenzoic anhydride, and the like.Examples of the compound represented by the formula: CH₂═CR¹COOSO₂R⁷include acrylic methanesulfonic anhydride, acrylic p-toluenesulfonicanhydride, methacrylic methanesulfonic anhydride, methacrylicp-toluenesulfonic anhydride, and the like.

Though a use amount of the polymerizable group introducing agent A isnot particularly limited, from the viewpoints of economy and easiness inpost-treatment, it is preferably from 0.8 to 5 mol, and more preferablyfrom 0.8 to 3 mol per 1 mol of the N-hydro-β-lactam derivative (2).

Examples of the basic substance which is used in the polymerizable groupintroducing step-A include an alkali metal hydride such as sodiumhydride, potassium hydride, and the like; an alkali metal hydroxide suchas sodium hydroxide, potassium hydroxide, and the like; an alkali metalcarbonate such as sodium carbonate, potassium carbonate, and the like; atertiary amine such as triethylamine, tributylamine,diazabicyclo[2.2.2]octane, and the like; a nitrogen-containingheterocyclic aromatic compound such as pyridine and the like; and so on.Of these, a tertiary amine and a nitrogen-containing heterocyclicaromatic compound are preferable.

Though a use amount of the basic substance is not particularly limited,from the viewpoints of economy and easiness in post-treatment, it ispreferably from 0.8 to 5 mol, and more preferably from 0.8 to 3 mol per1 mol of the N-hydro-β-lactam derivative (2).

The polymerizable group introducing step-A is carried out in thepresence or absence of a solvent.

The solvent is not particularly limited so far as it does not inhibitthe reaction. For example, there are preferably exemplified an aliphatichydrocarbon such as hexane, heptane, octane, and the like; an aromatichydrocarbon such as toluene, xylene, cymene, and the like; a halogenatedhydrocarbon such as methylene chloride, dichloroethane, and the like; anether such as tetrahydrofuran, diisopropyl ether, and the like; anitrile such as acetonitrile, benzonitrile, and the like; and so on. Ofthese, a halogenated hydrocarbon, an aromatic hydrocarbon, and a nitrileare preferable. The solvent may be used alone, or may be used inadmixture of two or more kinds thereof.

In the case of using the solvent, from the viewpoints of economy andeasiness in post-treatment, its use amount is preferably from 0.1 to 10parts by mass, and more preferably from 0.1 to 5 parts by mass per partby mass of the N-hydro-β-lactam derivative (2).

Though a reaction temperature of the polymerizable group introducingstep-A varies depending upon the kinds of the used polymerizable groupintroducing agent A, the N-hydro-β-lactam derivative (2), and the basicsubstance, in general, it is preferably from −50 to 80° C. Though areaction pressure is not particularly limited, in general, the reactionis carried out at atmospheric pressure.

Also, from the viewpoint of a yield of the N-acyl-β-lactam derivative(1), it is preferable that the polymerizable group introducing step-A iscarried out under an inert gas atmosphere such as nitrogen, argon, andthe like.

The reaction of the polymerizable group introducing step-A can bestopped by the addition of water and/or an alcohol. As the alcohol, forexample, there are preferably exemplified methanol, ethanol, n-propanol,isopropanol, and so on.

As to a use amount of water or the alcohol, it is preferable to usewater or the alcohol in an amount of 1 mol or more relative to theexcessive polymerizable group introducing agent A per 1 mol of theN-hydro-β-lactam derivative (2). So far as the use amount falls withinthis range, the excessively used polymerizable group introducing agent Acan be completely decomposed, and no by-product is produced.

Specific examples of the N-acyl-β-lactam derivative (1) wherein n is 0,which can be manufactured by the polymerizable group introducing step-A,are given below, but it should not be construed that the presentinvention is limited thereto.

(Polymerizable Group Introducing Step-B)

Next, the polymerizable group introducing step-B is described.

—Polymerizable Group Introducing Step-B1—

Among the connecting group introducing agents B1 which are used in thepolymerizable group introducing step-B1, examples of the compoundrepresented by the formula: X²-W-COX³ include chloroacetyl chloride,2-chloropropionyl chloride, 2-bromo-2-methylpropionyl bromide, and soon. Examples of the compound represented by the formula: X²-W-COOC(═O)R⁸include chloroacetic pivalic anhydride, chloroacetic2,4,6-trichlorobenzoic anhydride, 2-chloropropionic pivalic anhydride,2-chloropropionic 2,4,6-trichlorobenzoic anhydride, and so on. Examplesof the compound represented by the formula: X²-W-COOSO₂R⁹ includechloroacetic methanesulfonic anhydride, chloroacetic p-toluenesulfonicanhydride, 2-chloropropionic methanesulfonic anhydride,2-chloropropionic p-toluenesulfonic anhydride, and so on. Examples ofthe compound represented by the formula: (X²-W-CO)₂O includechloroacetic anhydride, 2-chloropropionic anhydride, and so on.

Though a use amount of the connecting group introducing agent B1 is notparticularly limited, from the viewpoints of economy and easiness inpost-treatment, it is preferably from 0.8 to 5 mol, and more preferablyfrom 0.8 to 3 mol per 1 mol of the N-hydro-β-lactam derivative (2).

Examples of the basic substance which is used in the polymerizable groupintroducing step-B1 include the same substances as those in the basicsubstance which is used in the polymerizable group introducing step-A.

Though a use amount of the basic substance is not particularly limited,from the viewpoints of economy and easiness in post-treatment, it ispreferably from 0.8 to 5 mol, and more preferably from 0.8 to 3 mol per1 mol of the N-hydro-β-lactam derivative (2).

The polymerizable group introducing step-B1 is carried out in thepresence or absence of a solvent.

The solvent is not particularly limited so far as it does not inhibitthe reaction, and examples thereof include the same solvents as thosewhich can be used in the polymerizable group introducing step-A. Thesolvent may be used alone, or may be used in admixture of two or morekinds thereof.

In the case of using the solvent, from the viewpoints of economy andeasiness in post-treatment, its use amount is preferably from 0.1 to 10parts by mass, and more preferably from 0.1 to 5 parts by mass per partby mass of the N-hydro-β-lactam derivative (2).

Though a reaction temperature of the polymerizable group introducingstep-B1 varies depending upon the kinds of the used connecting groupintroducing agent B1, the N-hydro-β-lactam derivative (2), and the basicsubstance, in general, it is preferably from −50 to 80° C. Though areaction pressure of the polymerizable group introducing step-B1 is notparticularly limited, in general, the reaction is carried out atatmospheric pressure.

Also, from the viewpoint of a yield of the desired compound, it ispreferable that the polymerizable group introducing step-B1 is carriedout under an inert gas atmosphere such as nitrogen, argon, and the like.

The reaction of the polymerizable group introducing step-B1 can bestopped by the addition of water and/or an alcohol. As the alcohol, forexample, there are preferably exemplified methanol, ethanol, n-propanol,isopropanol, and so on.

As to a use amount of water or the alcohol, it is preferable to usewater or the alcohol in an amount of 1 mol or more relative to theexcessive connecting group introducing agent B1 per 1 mol of theN-hydro-β-lactam derivative (2). So far as the use amount falls withinthis range, the excessively used connecting group introducing agent B1can be completely decomposed, and no by-product is produced.

—Polymerizable Group Introducing Step-B2—

Examples of the polymerizable group introducing agent B2 which is usedin the polymerizable group introducing step-B2 include sodium acrylate,potassium acrylate, sodium methacrylate, potassium methacrylate, and thelike. As a preparation method thereof, from the viewpoint of simplicityof the operations, a method of preparing the polymerizable groupintroducing agent B2 by allowing acrylic acid or methacrylic acid toreact with a base such as sodium hydroxide, sodium carbonate, potassiumhydroxide, potassium carbonate, and the like in a reaction system ispreferable.

From the viewpoints of economy and easiness in post-treatment, a useamount of the polymerizable group introducing agent B2 is preferablyfrom 0.8 to 5 mol, and more preferably from 0.8 to 3 mol per 1 mol ofthe product of the polymerizable group introducing step-B1.

In the polymerizable group introducing step-B2, if desired, it ispreferable to use, as an activating agent, potassium iodide, sodiumiodide, tetrabutylammonium iodide, tetrabutylammonium bromide, or thelike.

In the case of using the activating agent, its use amount is preferablyfrom 0.001 to 0.5 mol, and from the viewpoints of easiness inpost-treatment and economy, its use amount is more preferably from 0.005to 0.3 mol per 1 mol of the product of the polymerizable groupintroducing step-B1.

The polymerizable group introducing step-B2 is carried out in thepresence or absence of a solvent.

The solvent is not particularly limited so far as it does not inhibitthe reaction. Examples thereof include an aliphatic hydrocarbon such ashexane, heptane, octane, and the like; an aromatic hydrocarbon such astoluene, xylene, cymene, and the like; a halogenated hydrocarbon such asmethylene chloride, dichloroethane, and the like; an ether such astetrahydrofuran, diisopropyl ether, and the like; and an amide such asN,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, andthe like. The solvent may be used alone, or may be used in admixture oftwo or more kinds thereof.

In the case of using the solvent, from the viewpoints of economy andeasiness in post-treatment, its use amount is preferably from 0.1 to 10parts by mass, and more preferably from 0.1 to 5 parts by mass per partby mass of the product of the polymerizable group introducing step-B1.

Though a reaction temperature of the polymerizable group introducingstep-B2 varies depending upon the kinds of the used polymerizable groupintroducing agent B2, the product of the polymerizable group introducingstep-B1, and the basic substance, in general, it is preferably from −50to 80° C. Though a reaction pressure is not particularly limited, ingeneral, the reaction is carried out at atmospheric pressure.

Specific examples of the N-acyl-β-lactam derivative (1) wherein n is 1,which can be manufactured by the polymerizable group introducing step-B,are given below, but it should not be construed that the presentinvention is limited thereto.

If desired, it is preferable that the N-acyl-β-lactam derivative (1)obtained through the polymerizable group introducing step-A or thepolymerizable group introducing step-B is separated and purified in theusual way.

For example, after the reaction mixture obtained by the polymerizablegroup introducing step-A or the polymerizable group introducing step-Bis washed with water and then concentrated, the N-acyl-P-lactamderivative (1) can be separated and purified by a method which is usedfor usual separation and purification of an organic compound, such asdistillation, column chromatography, recrystallization, and the like.

Also, if desired, it is possible to reduce a content of metals of theobtained N-acyl-β-lactam derivative (1) by adding a chelating agent suchas nitrilotriacetate, ethylenediaminetetraacetic acid, and the like,followed by filtration or a treatment with a metal-removing filter suchas Zeta Plus (a trade name, manufactured by Cuno Inc.), Protego (a tradename, manufactured by Nihon Mykrolis Ltd.), and the like.

Incidentally, the starting N-hydro-β-lactam derivative (2) can bemanufactured by allowing a corresponding olefin compound to react withchlorosulfonyl isocyanate and then hydrolyzing the chlorosulfonyl groupin the presence of a reducing agent such as sodium sulfite, sodiumhydrogensulfite, and the like.

[Polymer]

The polymer of the present invention is one obtained by polymerizing theforegoing N-acyl-β-lactam derivative (1) alone or one obtained bycopolymerizing the N-acyl-β-lactam derivative (1) with otherpolymerizable compound. The “other polymerizable compound” as referredto herein is a compound from which “other constituent unit” as describedlater is derived.

The polymer of the present invention contains a constituent unit on thebasis of the N-acyl-β-lactam derivative (1) (hereinafter referred to as“constituent unit (1′)”) in an amount of more than 0% by mole and up to100% by mole, and from the viewpoint of a reduction of LWR, in an amountof preferably from 10 to 80% by mole, more preferably from 20 to 70% bymole, and still more preferably from 20 to 60% by mole.

Specific examples of the constituent unit (1′) are given below, but itshould not be construed that the present invention is limited thereto.

Examples of the constituent unit on the basis of the foregoing otherpolymerizable compound include constituent units (a1) to (a5) asdescribed below, and the constituent unit is properly chosen dependingupon an application of the resist composition, desired properties, andthe like.

(Constituent Unit (a1))

The constituent unit (a1) is a constituent unit which is derived from anacid dissociable dissolution inhibiting group-containing acrylic ester.The acid dissociable dissolution inhibiting group is one which informing a resist pattern as the resist composition, not only has alkalidissolution inhibiting properties so as to make the whole of the polymersparingly soluble in an alkaline developing solution prior to thedissociation but is dissociated by an acid generated from the acidgenerator component upon exposure, thereby increasing the solubility ofthe whole of this polymer in an alkaline developing solution.

Though such a constituent unit (a1) is not particularly limited,examples thereof include the following structural units (a1-1) to(a1-49).

In the foregoing constituent units (a1-1) to (a1-49), R¹¹ represents ahydrogen atom or a halogenated or non-halogenated alkyl group having acarbon number of from 1 to 5; and each of R¹² and R¹³ independentlyrepresents an alkyl group having a carbon number of from 1 to 10.

Examples of the halogenated or non-halogenated alkyl group having acarbon number of from 1 to 5, which R¹¹ represents, include a methylgroup, a trifluoromethyl group, an ethyl group, a pentafluoroethylgroup, various propyl groups (it is meant by the term “various” that alinear group and all of branched groups are included; hereinafter thesame), various butyl groups, and so on. Incidentally, R¹¹ is preferablya hydrogen atom or a methyl group.

Examples of the alkyl group having a carbon number of from 1 to 10,which each of R¹² and R¹³ independently represents, include a methylgroup, an ethyl group, various propyl groups, various butyl groups,various hexyl groups, various octyl groups, various decyl groups, and soon. Of these, an alkyl group having a carbon number of from 1 to 5 ispreferable, and a methyl group and an ethyl group are more preferable.

Among the foregoing constituent units (a1-1) to (a1-49), from theviewpoint of an improving effect of LWR, (a1-1) is preferable.

The foregoing constituent unit (a1) may be composed of only one kind, ormay be composed of two or more kinds thereof.

In the case where the polymer has the constituent unit (a1), though aproportion of the constituent unit (a1) is not particularly limited,from the standpoints of sensitivity, resolution and adhesion to asubstrate of the resist film, it is preferably from 10 to 80% by mole,and more preferably from 20 to 70% by mole in the whole of theconstituent units constituting the polymer of the present invention.When the proportion of the constituent unit (a1) falls within thisrange, at the time of forming a resist composition, a pattern can beeasily obtained, and a balance with other constituent units can betaken.

(Constituent Unit (a2))

The constituent unit (a2) is a constituent unit which is derived from anacrylic ester having a lactone-containing group. The lactone-containinggroup as referred to herein means a group containing one lactone ringcontaining a —O—C(O)— structure. In this specification, with respect tothe ester group of the foregoing acrylic ester, the ester group havingonly a lactone ring as the cyclic compound is referred to as “monocyclicgroup”, and in the case of further having other cyclic structure, theester group is referred to as “polycyclic group” regardless of astructure thereof.

In the case of using the polymer for the formation of a resist film, thelactone-containing group of the constituent unit (a2) is effective forenhancing the adhesion of the resist film to a substrate or enhancingthe affinity with a water-containing developing solution.

Examples of the lactone-containing monocyclic group include a groupobtained by eliminating one hydrogen atom from γ-butyrolactone. Examplesof the lactone-containing polycyclic group include a group obtained byeliminating one hydrogen atom from a lactone ring-containingbicycloalkane, tricycloalkane or tetracycloalkane.

More specific examples of the constituent unit (a2) include thefollowing constituent units (a2-1) to (a2-6), but it should not beconstrued that the present invention is limited thereto.

In the formulae, R¹⁴ represents a hydrogen atom or a halogenated ornon-halogenated alkyl group having a carbon number of from 1 to 5. Eachof R¹⁵ and R¹⁶ independently represents a hydrogen atom, an alkyl grouphaving a carbon number of from 1 to 5, an alkoxy group having a carbonnumber of from 1 to 5, or —COOR¹⁷ (R¹⁷ is an alkyl group having a carbonnumber of from 1 to 3). W′ represents an alkylene group having a carbonnumber of from 1 to 10 or a cycloalkylene group having a carbon numberof from 3 to 10. A represents an alkylene group having a carbon numberof from 1 to 5 or an oxygen atom. Also, i represents 0 or 1.

Examples of the halogenated or non-halogenated alkyl group having acarbon number of 1 to 5, which R¹⁴ represents, include the same groupsas those in the case of R¹¹. Of these, a methyl group, an ethyl group,and a trifluoromethyl group are preferable, with a methyl group and anethyl group being more preferable.

Examples of the alkyl group having a carbon number of from 1 to 5, whicheach of R¹⁵ and R¹⁶ independently represents, include a methyl group, anethyl group, various propyl groups, and various butyl groups. Of these,a methyl group and an ethyl group are preferable. —COOR¹⁷ is preferably—COOCH₃.

Incidentally, from the viewpoint of easiness in industrial availability,it is preferable that all of R¹⁵ and R¹⁶ are a hydrogen atom (namely, nospecial substituent is present on the foregoing constituent unit).

The alkylene group having a carbon number of from 1 to 10, which Wrepresents, may be either linear or branched. Examples of the alkylenegroup include a methylene group, an ethylene group, a propylene group, atrimethylene group, and so on. Examples of the cycloalkylene grouphaving a carbon number of from 3 to 10 include a cyclopentane-diylgroup, a cyclohexane-diyl group, and so on.

Examples of the alkylene group having a carbon number of from 1 to 5,which A represents, include a methylene group, a 1,2-ethylene group, a1,1-ethylene group, an isopropylene group, and so on.

Specific examples of the foregoing constituents (a2-1) to (a2-6) aregiven below in succession, but it should not be construed that thepresent invention is limited thereto.

The foregoing constituent unit (a2) may be composed of only one kind, ormay be composed of two or more kinds thereof.

The constituent unit (a2) is preferably composed of at least one memberselected from the group consisting of the foregoing constituent units(a2-1) to (a2-6), and preferably composed of at least one memberselected from the general formulae (a2-1) to (a2-3). More specifically,the constituent unit (a2) is preferably composed of at least one memberselected from the group consisting of the constituent units (a2-1-1),(a2-1-2), (a2-2-1), (a2-2-2), (a2-3-1), (a2-3-2), (a2-3-9) and(a2-3-10).

In the case where the polymer has the constituent unit (a2), aproportion of the constituent unit (a2) is preferably from 1 to 60% bymole, more preferably from 10 to 55% by mole, and still more preferablyfrom 20 to 55% by mole relative to the whole of the constituent unitsconstituting the polymer of the present invention. When the proportionof the constituent unit (a2) falls within this range, the effects to bebrought by incorporating the constituent unit (a2) are sufficientlyobtained, and a balance with other constituent units can be taken.

(Constituent Unit (a3))

The constituent unit (a3) is a constituent unit which is derived from anacrylic ester having a polar group-containing aliphatic hydrocarbongroup. By the fact that the polymer has the constituent unit (a3), thehydrophilicity of the polymer is enhanced; and at the time of forming apositive working resist pattern by using a polymer for a base materialcomponent of a positive working resist composition, the affinity withthe developing solution (alkaline aqueous solution) is enhanced, and thealkali solubility in an exposed area is enhanced, thereby contributingto an enhancement of the resolution.

Examples of the polar group include a hydroxyl group, a cyano group, acarboxyl group, and so on. Of these, a hydroxyl group is preferable. Thepolar group which the polar group-containing aliphatic hydrocarbon grouphas may be one kind or two or more kinds thereof.

As the preferred constituent unit (a3), there are exemplified thefollowing constituent units (a3′) and (a3″) and so on.

The constituent unit (a3′) is a constituent unit which is derived froman acrylic ester having a hydroxyl group-containing alicyclichydrocarbon group. The “hydroxyl group-containing alicyclic hydrocarbongroup” as referred to herein is a group in which a hydroxyl group isbonded to an alicyclic hydrocarbon group. The hydroxyl group may bebonded directly to the aliphatic ring, or may be bonded indirectly tothe aliphatic ring as, for example, a hydroxyalkyloxy group.

The alkyl group in the hydroxyalkyloxy group is preferably linear orbranched. A carbon number of the alkyl group is preferably from 2 to 5,more preferably from 2 to 4, and still more preferably 2 or 3. Ahydroxyl group number in the hydroxyalkyloxy group is preferably from 1to 4, more preferably from 1 to 3, and still more preferably 1 or 2. Thehydroxyl group is more preferably a primary hydroxyl group or asecondary hydroxyl group, and still more preferably a primary hydroxylgroup.

The hydroxyalkyloxy group is preferably a monohydroxyalkyloxy group or adihydroxyalkyloxy group; and more preferably a monohydroxyethyloxygroup, a monohydroxypropyloxy group, or a dihydroxypropyloxy group.

A number of a hydroxyl group or groups bonded to the alicyclichydrocarbon group is preferably from 1 to 3, and more preferably 1. Thealicyclic hydrocarbon group may have a substituent, or may beunsubstituted. Examples of the substituent include an alkyl group havinga carbon number of from 1 to 5, a fluorine atom, a fluorineatom-substituted fluorinated alkyl group having a carbon number of from1 to 5, an oxygen atom (═O), and so on.

In the alicyclic hydrocarbon group, a part of carbon atoms constitutingthe ring may be substituted with a hetero atom such as an oxygen atom, anitrogen atom, a sulfur atom, and the like.

Though the alicyclic hydrocarbon group may be either saturated orunsaturated, from the standpoints of high transparency to an ArF excimerlaser, etc. and excellent resolution or depth of focus (DOF), etc., itis preferably saturated.

Though the alicyclic hydrocarbon group may be a monocyclic group or apolycyclic group, it is preferably a polycyclic group. Also, a carbonnumber of the alicyclic hydrocarbon group is preferably from 5 to 15.

Specific examples of the alicyclic hydrocarbon group (the moiety fromwhich the hydroxyl group or groups have been removed) in the hydroxylgroup-containing alicyclic hydrocarbon group include the following. Asthe monocyclic group, there are exemplified a group obtained byeliminating two or more hydrogen atoms from a cycloalkane, and so on.More specifically, there is exemplified a group obtained by eliminatingtwo or more hydrogen atoms from cyclopentane or cyclohexane, and a groupobtained by eliminating two hydrogen atoms from cyclohexane ispreferable.

As the polycyclic group, there are exemplified a group obtained byeliminating two or more hydrogen atoms from a bicycloalkane, atricycloalkane, a tetracycloalkane, or the like, and so on. Morespecifically, there are exemplified a group obtained by eliminating twoor more hydrogen atoms from a polycycloalkane such as adamantane,norbornane, isobornane, tricyclodecane, tetracyclododecane, and thelike, and so on.

Of these, from the viewpoint of easiness in industrial availability, agroup obtained by eliminating two hydrogen atoms from cyclohexane,adamantane, norbornane, or tetracyclododecane is preferable, with agroup obtained by eliminating two hydrogen atoms from adamantane ornorbornane being more preferable.

In the constituent unit (a3′), it is preferable that the hydroxylgroup-containing alicyclic hydrocarbon group is bonded to an oxygen atomof an end of a carbonyloxy group [—C(O)—O—] of an acrylic ester.

As a preferred specific example of the constituent unit (a3′), forexample, there is exemplified the following constituent unit (a3′-1).

In the foregoing constituent unit, R¹⁸ represents a hydrogen atom or ahalogenated or non-halogenated alkyl group having a carbon number offrom 1 to 5. R¹⁹ represents a hydrogen atom or a hydroxyalkyl group.Also, j represents an integer of from 1 to 3.

Examples of the halogenated or non-halogenated alkyl group having acarbon number of from 1 to 5, which R¹⁸ represents, include the samegroups as those in the case of R¹¹. Of these, a methyl group, an ethylgroup, and a trifluoromethyl group are preferable, with a methyl groupand an ethyl group being more preferable.

The alkyl group in the hydroxyalkyl group which R¹⁹ represents may beeither linear or branched. A carbon number of the alkyl group ispreferably from 1 to 5, and more preferably from 1 to 4. The alkyl groupis still more preferably a methyl group, an n-propyl group, or anisopropyl group.

A hydroxyl group number in the hydroxyalkyl group of R¹⁹ is preferablyfrom 1 to 4, more preferably from 1 to 3, and still more preferably 1 or2. The hydroxyl group is more preferably a primary hydroxyl group or asecondary hydroxyl group, and still more preferably a primary hydroxylgroup.

In the present invention, R¹⁹ is preferably a monohydroxyalkyl group, adihydroxyalkyl group, or a hydrogen atom; and more preferably amonohydroxyethyl group, a monohydroxypropyl group, a dihydroxypropylgroup, or a hydrogen atom.

j is preferably 1 or 2, and more preferably 1. In the case where j is 1,it is preferable that —OR¹⁹ is bonded at the 3-position of the adamantylgroup. In the case where j is 2, it is preferable that —OR¹⁹ is bondedat the 3-position and 5-position of the adamantyl group.

As the constituent unit (a3′-1), it is preferable that j is 1; and it isespecially preferable that —OR¹⁹ is bonded at the 3-position of theadamantyl group. That is, as the constituent unit (a3′), a constituentunit represented by the following general formula (a3′-1-1) (in thefollowing constituent unit, R¹⁸ and R¹⁹ are the same as defined above)is preferable.

The constituent unit (a3″) is a constituent unit which is derived froman acrylic acid not having a cyclic structure, namely an alicyclichydrocarbon group or an aromatic hydrocarbon group, and having analcoholic hydroxyl group in a side chain thereof.

Examples of the constituent unit having an alcoholic hydroxyl group in aside chain thereof include a hydroxyalkyl group-containing constituentunit.

In the hydroxyalkyl group, the alkyl group may be either linear orbranched. A carbon number of the alkyl group is preferably from 1 to 20,more preferably from 1 to 16, and still more preferably from 1 to 12. Ahydroxyl group number is preferably 1 or 2, and more preferably 1.

For example, the hydroxyalkyl group may be bonded directly to the carbonatom at the α-position of the main chain (the moiety in which theethylenically double bond of acrylic acid is cleaved), or may besubstituted with a hydrogen atom of the carboxyl group of acrylic acidto constitute an ester. In the constituent unit (a3″), it is preferablethat the hydroxyalkyl group is present in at least one or both of them.

Incidentally, in the case where the hydroxyalkyl group is not bonded atthe α-position, a halogenated or non-halogenated alkyl group may bebonded to the carbon atom at the α-position. With respect to thehalogenated or non-halogenated alkyl group, there are exemplified thesame groups as those in the case of R¹¹, and the same alkyl groups arepreferable.

The constituent unit (a3″) is preferably a constituent unit representedby the following general formula (a3″-1).

In the foregoing constituent unit, R²⁰ represents a hydrogen atom, ahalogenated or non-halogenated alkyl group, or a hydroxyalkyl group; andR²¹ represents an alkyl group or a hydroxyalkyl group, provided that atleast one of R²⁰ and R²¹ represents a hydroxyalkyl group.

The hydroxyalkyl group which R²⁰ represents is preferably a linear orbranched hydroxyalkyl group having a carbon number of not more than 10,and more preferably a linear or branched hydroxyalkyl group having acarbon number of from 1 to 8. Though a hydroxyl group number in thehydroxyalkyl group is not particularly limited, it is in general 1.Also, the hydroxyl group is more preferably a primary or secondaryhydroxyl group, and still more preferably a primary hydroxyl group. Thehydroxyalkyl group which R²⁰ represents is yet still more preferably ahydroxymethyl group or a hydroxyethyl group.

A carbon number of the halogenated or non-halogenated alkyl group whichR²⁰ represents is preferably not more than 10, more preferably from 1 to8, and still more preferably 1 or 2. Examples of the halogenated ornon-halogenated alkyl group which R²⁰ represents include a methyl group,a trifluoromethyl group, an ethyl group, a pentafluoroethyl group,various propyl groups, various butyl groups, and so on.

Examples of the alkyl group which R²¹ represents include a methyl group,an ethyl group, various propyl groups, various butyl groups, variousheptyl groups, various octyl groups, various decyl groups, variousdodecyl groups, and so on. The alkyl group is preferably an alkyl grouphaving a carbon number of not more than 10, more preferably an alkylgroup having a carbon number of from 1 to 8, and still more preferably amethyl group or an ethyl group.

The hydroxyalkyl group which R²¹ represents is preferably a linear orbranched hydroxyalkyl group having a carbon number of not more than 10,more preferably a linear or branched hydroxyalkyl group having a carbonnumber of from 2 to 8, and still more preferably a hydroxyethyl group.Though a hydroxyl group number is not particularly limited, it is ingeneral 1. Also, the hydroxyl group is more preferably a primary orsecondary hydroxyl group, and still more preferably a primary hydroxylgroup.

Also, in addition to the foregoing constituent units (a3′) and (a3″),the following constituent unit (a3-2) is also preferably exemplified asthe constituent unit (a3).

In the foregoing constituent unit, R²² represents a hydrogen atom or ahalogenated or non-halogenated alkyl group having a carbon number offrom 1 to 5; and k represents an integer of from 1 to 3.

Examples of the halogenated or non-halogenated alkyl group having acarbon number of from 1 to 5, which R²² represents, include the samegroups as those in the case of R¹¹.

k is preferably 1, and it is preferable that the cyano group is bondedat the 5-position or 6-position of the norbornyl group.

The foregoing constituent unit (a3) may be composed of only one kind, ormay be composed of two or more kinds thereof.

In the case where the polymer has the constituent unit (a3), aproportion of the constituent unit (a3) is preferably from 5 to 50% bymole, more preferably from 5 to 40% by mole, and still more preferablyfrom 5 to 25% by mole relative to the whole of the constituent unitsconstituting the polymer of the present invention.

Also, in the case where the polymer has the constituent unit (a3), theconstituent unit (a3) is preferably the constituent unit (a3′), morepreferably a constituent unit of the constituent unit (a3′-1) whereinR¹⁹ is a hydrogen atom, and still more preferably a constituent unit ofthe constituent unit (a3′-1-1) wherein R¹⁹ is a hydrogen atom.

(Constituent Unit (a4))

The constituent unit (a4) is a constituent unit which is derived from a(meth)acrylic acid alicyclic hydrocarbon ester.

The constituent unit (a4) is effective for regulating the polarity ofthe polymer or regulating thermal physical properties of the polymer.

The alicyclic hydrocarbon group that is an alcohol residue of the (meth)acrylic acid alicyclic hydrocarbon ester may be monocyclic orpolycyclic, and a carbon number forming the ring is preferably from 3 to12, and more preferably from 6 to 12. From the viewpoint of easiness inindustrial availability, the alicyclic hydrocarbon group is still morepreferably a tricyclodecanyl group, an adamantyl group, atetracyclododecanyl group, an isobornyl group, or a norbornyl group.

The alicyclic hydrocarbon group may have a substituent. The substituentis preferably a linear or branched alkyl group having a carbon number offrom 1 to 5. Examples of the linear or branched alkyl group having acarbon number of from 1 to 5 include a methyl group, an ethyl group,various propyl groups, various butyl groups, and so on.

Specifically, the following constituent units are exemplified as theconstituent unit (a4), but it should not be construed that the presentinvention is limited thereto.

The foregoing constituent unit (a4) may be composed of only one kind, ormay be composed of two or more kinds thereof.

In the case where the polymer has the constituent unit (a4), aproportion of the constituent unit (a4) is preferably from 1 to 30% bymole, and more preferably from 10 to 20% by mole relative to the wholeof the constituent units constituting the polymer of the presentinvention.

(Constituent Unit (a5))

The constituent unit (a5) is other constituent unit which is notclassified into the foregoing constituent units (1′) and (a1) to (a4).As the constituent unit (a5), all of constituent units which havehitherto been known as a constituent unit of a polymer for photoresistfor ArF excimer laser or KrF excimer laser (preferably for ArF excimerlaser) or the like can be used. Specifically, the following constituentunits are exemplified as the constituent unit (a5), but it should not beconstrued that the present invention is limited thereto.

As described above, the polymer of the present invention may be acopolymer of the N-acyl-β-lactam derivative (1) and other polymerizablecompound, namely a copolymer composed of the constituent unit (1′) andother constituent unit.

As the preferred structure of the copolymer, there are exemplified thefollowing copolymers (A1) to (A6) and so on.

Copolymer (A1): Copolymer having at least the constituent units (1′) and(a1)

Copolymer (A2): Copolymer having at least the constituent units (1′) and(a2)

Copolymer (A3): Copolymer having at least the constituent units (1′) and(a3)

Copolymer (A4): Copolymer having at least the constituent units (1′) and(a4)

Copolymer (A5): Copolymer having at least the constituent units (1′),(a1) and (a2)

Copolymer (A6): Copolymer having at least the constituent units (1′),(a1) and (a3)

(Manufacturing Method of Polymer)

The polymer can be manufactured by means of radical polymerizationaccording to the usual way. In particular, as a method of synthesizingthe polymer having a small molecular weight distribution, there can beexemplified living radical polymerization and so on. In a generalradical polymerization method, one or more kinds of the N-acyl-β-lactamderivative (1) and if desired, one or more kinds of monomerscorresponding to the foregoing constituent units (a1) to (a5)(hereinafter referred to as “copolymerization monomer”) are polymerizedin the presence of a radical polymerization initiator and solvent and ifdesired, a chain transfer agent.

A method of carrying out the radical polymerization is not particularlylimited, and a customary method which is adopted in manufacturing, forexample, an acrylic polymer, such as a solution polymerization method,an emulsion polymerization method, a suspension polymerization method, abulk polymerization method, and the like, can be adopted.

Examples of the radical polymerization initiator which is used for themanufacture of the polymer of the present invention include ahydroperoxide compound such as t-butyl hydroperoxide, cumenehydroperoxide, and the like; a dialkyl peroxide compound such asdi-t-butyl peroxide, t-butyl-α-cumyl peroxide, di-α-cumyl peroxide, andthe like; a diacyl peroxide compound such as benzoyl peroxide,diisobutyryl peroxide, and the like; an azo compound such as2,2′-azobisisobutyronitrile, dimethyl-2,2′-azobisisobutyrate, and thelike; and so on.

Though a use amount of the radical polymerization initiator can beproperly chosen depending upon kinds and use amounts of theN-acyl-β-lactam derivative (1), the copolymerization monomer, the chaintransfer agent, and the solvent, each of which is used for thepolymerization reaction; and a copolymerization condition such as apolymerization temperature and the like, it is in general from 0.005 to0.2 mol, and preferably from 0.01 to 0.15 mol per 1 mol of the whole ofthe polymerizable compounds [referring to a total sum amount of theN-acyl-β-lactam derivative (1) and the copolymerization monomer;hereinafter the same].

Examples of the chain transfer agent which is used for the manufactureof the polymer of the present invention include a thiol compound such asdodecane thiol, mercapto ethanol, mercapto propanol, mercapto aceticacid, mercapto propionic acid, and the like. Such a thiol compound maybe used alone or in admixture of two or more kinds thereof.

In the case of using the chain transfer agent, its use amount is ingeneral from 0.005 to 0.2 mol, and preferably from 0.01 to 0.15 mol per1 mol of the whole of the polymerizable compounds.

The manufacture of the polymer of the present invention is in generalcarried out in the presence of a solvent.

The solvent is not particularly limited so far as it does not inhibitthe polymerization reaction. Examples thereof include a glycol ethersuch as propylene glycol monoethyl ether, propylene glycol monomethylether acetate, ethylene glycol monomethyl ether, ethylene glycolmonomethyl ether acetate, ethylene glycol monomethyl ether propionate,ethylene glycol monobutyl ether, ethylene glycol monobutyl etheracetate, diethylene glycol dimethyl ether, and the like; an ester suchas ethyl lactate, methyl 3-methoxypropionate, methyl acetate, ethylacetate, propyl acetate, and the like; a ketone such as acetone, methylethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methylamyl ketone, cyclopentanone, cyclohexanone, and the like; an ether suchas diethyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran,1,4-dioxane, and the like; and so on. Such a solvent may be used aloneor in admixture of two or more kinds thereof.

A use amount of the solvent is in general from 0.5 to 20 parts by mass,and from the viewpoint of economy, preferably from 1 to 10 parts bymass, per part by mass of the whole of the polymerizable compounds.

In manufacturing the polymer of the present invention, a polymerizationtemperature is in general from 40 to 150° C., and from the viewpoint ofstability of the produced polymer, preferably from 60 to 120° C.

A manufacturing time of the polymer of the present invention variesdepending upon kinds and use amounts of the N-acyl-β-lactam derivative(1), the copolymerization monomer, the polymerization initiator, and thesolvent; and a copolymerization condition such as a temperature of thepolymerization reaction and the like, it is in general from 30 minutesto 48 hours, and more preferably from one hour to 24 hours.

The thus obtained polymer can be isolated by a usual operation such asreprecipitation and the like. The isolated polymer can also be dried bymeans of vacuum drying or the like.

Examples of a solvent which is used for the foregoing operation ofreprecipitation include an aliphatic hydrocarbon such as pentane,hexane, and the like; an alicyclic hydrocarbon such as cyclohexane andthe like; an aromatic hydrocarbon such as benzene, xylene, and the like;a halogenated hydrocarbon such as methylene chloride, chloroform,chlorobenzene, dichlorobenzene, and the like; a nitrated hydrocarbonsuch as nitromethane and the like; a nitrile such as acetonitrile,benzonitrile, and the like; an ether such as diethyl ether, diisopropylether, tetrahydrofuran, 1,4-dioxane, and the like; a ketone such asacetone, methyl ethyl ketone, and the like; a carboxylic acid such asacetic acid and the like; an ester such as ethyl acetate, butyl acetate,and the like; a carbonate such as dimethyl carbonate, diethyl carbonate,ethylene carbonate, and the like; an alcohol such as methanol, ethanol,propanol, isopropyl alcohol, butanol, and the like; and water. Such asolvent may be used alone or in admixture of two or more kinds thereof.

Though a use amount of the solvent varies depending upon the kind of thepolymer and the kind of the solvent, in general, it is preferably from0.5 to 100 parts by mass, and from the viewpoint of economy, morepreferably from 1 to 50 parts by mass, per part by mass of the polymer.

(Weight Average Molecular Weight (Mw))

Though a weight average molecular weight (Mw) of the polymer is notparticularly limited, when it is preferably from 500 to 50,000, and morepreferably from 1,000 to 30,000, its usefulness as a component of aphotoresist composition as described later is high. Such Mw is a valuemeasured according to the method described in the Examples.

[Photoresist Composition]

The photoresist composition of the present invention contains a photoacid generator and a solvent and if desired, a basic compound, asurfactant, and other additives as described below, together with theforegoing polymer.

(Photo Acid Generator)

The photo acid generator is not particularly limited, and a known photoacid generator which has hitherto been generally used for a chemicalamplification type resist can be used. Examples of the photo acidgenerator include an onium salt based photo acid generator such as aniodonium salt, a sulfonium salt, and the like; an oxysulfonate basedphoto acid generator; a bisalkyl or bisaryl sulfonyl diazomethane basedphoto acid generator; a nitrobenzyl sulfonate based photo acidgenerator; an imino sulfonate based photo acid generator; a disulfonebased photo acid generator; and so on. Such a photo acid generator maybe used alone or in admixture of two or more kinds thereof. Of these, anonium salt based photo acid generator is preferable. Furthermore, fromthe viewpoint of the fact that the intensity of the generated acid isstrong, the following fluorine-containing onium salts containing afluorine-containing alkylsulfonic acid ion as an anion are preferable.

Specific examples of the fluorine-containing onium salt includetrifluoromethanesulfonate or nonafluorobutanesulfonate ofdiphenyliodonium; trifluoromethanesulfonate or nonafluorobutanesulfonateof bis(4-tert-butylphenyl)iodonium; trifluoromethanesulfonate,heptafluoropropanesulfonate or nonafluorobutanesulfonate oftriphenylsulfonium; trifluoromethanesulfonate,heptafluoropropanesulfonate or nonafluorobutanesulfonate oftri(4-methylphenyl)sulfonium; trifluoromethanesulfonate,heptafluoropropanesulfonate or nonafluorobutanesulfonate ofdimethyl(4-hydroxynaphthyl)sulfonium; trifluoromethanesulfonate,heptafluoropropanesulfonate or nonafluorobutanesulfonate ofmonophenyldimethylsulfonium; trifluoromethanesulfonate,heptafluoropropanesulfonate or nonafluorobutanesulfonate ofdiphenylmonomethylsulfonium; trifluoromethanesulfonate,heptafluoropropanesulfonate or nonafluorobutanesulfonate of(4-methylphenyl)diphenylsulfonium; trifluoromethanesulfonate,heptafluoropropanesulfonate or nonafluorobutanesulfonate of(4-methoxyphenyl)diphenylsulfonium; trifluoromethanesulfonate,heptafluoropropanesulfonate or nonafluorobutanesulfonate oftri(4-tert-butyl)phenylsulfonium; and so on. Such a fluorine-containingonium salt may be used alone or in admixture of two or more kindsthereof.

From the viewpoint of ensuring sensitivity and developability of thephotoresist composition, in general, a blending amount of the photo acidgenerator is preferably from 0.1 to 30 parts by mass, and morepreferably from 0.5 to 10 parts by mass based on 100 parts by mass ofthe polymer.

(Solvent)

Examples of the solvent which is blended in the photoresist compositioninclude a glycol ether such as propylene glycol monoethyl ether,propylene glycol monomethyl ether acetate, ethylene glycol monomethylether, ethylene glycol monomethyl ether acetate, ethylene glycolmonomethyl ether propionate, ethylene glycol monobutyl ether, ethyleneglycol monobutyl ether acetate, diethylene glycol dimethyl ether, andthe like; an ester such as ethyl lactate, methyl 3-methoxypropionate,methyl acetate, ethyl acetate, propyl acetate, and the like; a ketonesuch as acetone, methyl ethyl ketone, methyl isopropyl ketone, methylisobutyl ketone, methyl amyl ketone, cyclopentanone, cyclohexanone, andthe like; an ether such as diethyl ether, diisopropyl ether, dibutylether, tetrahydrofuran, 1,4-dioxane, and the like; and so on. Such asolvent may be used alone or in admixture of two or more kinds thereof.

In general, a blending amount of the solvent is preferably from 1 to 50parts by mass, and preferably from 2 to 25 parts by mass per part bymass of the polymer.

(Basic Compound)

For the purpose of enhancing the resolution while suppressing adiffusion rate of the acid in the photoresist film, if desired, a basiccompound can be blended in an amount in the range where properties ofthe photoresist composition are not inhibited, in the photoresistcomposition. As such a basic compound, there can be exemplified an amidesuch as formamide, N-methylformamide, N,N-dimethylformamide, acetamide,N-methylacetamide, N,N-dimethylacetamide, N-(1-adamantyl)acetamide,benzamide, N-acetylethanolamine, 1-acetyl-3-methylpiperidine,pyrrolidone, N-methylpyrrolidone, ε-caprolactam, δ-valerolactam,2-pyrrolidinone, acrylamide, methacrylamide, t-butyl acrylamide,methylenebisacrylamide, methylenebismethacrylamide,N-methylolacrylamide, N-methoxyacrylamide, diacetoneacrylamide, and thelike; and an amine such as pyridine, 2-methylpyridine, 4-methylpyridine,nicotine, quinoline, acridine, imidazole, 4-methylimidazole,benzimidazole, pyrazine, pyrazole, pyrrolidine,N-t-butoxycarbonylpyrrolidine, piperidine, tetrazole, morpholine,4-methylmorpholine, piperazine, 1,4-diazabicyclo[2.2.2]octane,tributylamine, tripentylamine, trihexylamine, triheptylamine,trioctylamine, triethanolamine, and the like. Such a basic compound canbe used alone or in admixture of two or more kinds thereof.

In the case of blending the basic compound, though its blending amountvaries depending upon the kind of the used basic compound, in general,it is preferably from 0.01 to 10 mol, and more preferably from 0.05 to 1mol per 1 mol of the photo acid generator.

(Surfactant)

For the purpose of enhancing the coatability, if desired, a surfactantcan be blended in an amount in the range where properties of thephotoresist composition is not inhibited, in the photoresistcomposition.

Examples of such a surfactant include polyoxyethylene lauryl ether,polyoxyethylene stearyl ether, polyoxyethylene oleyl ether,polyoxyethylene n-octylphenyl ether, and so on. Such a surfactant may beused alone or in admixture of two or more kinds thereof.

In the case of blending the surfactant, its blending amount is ingeneral not more than 2 parts by mass based on 100 parts by mass of thepolymer.

(Other Additives)

Furthermore, a sensitizer, a halation preventing agent, a shapeimproving agent, a storage stabilizer, a defoaming agent, and the likecan be blended as other additives in an amount in the range whereproperties of the photoresist composition are not impaired, in thephotoresist composition.

(Formation of Photoresist Pattern)

A prescribed resist pattern can be formed by coating the photoresistcomposition on a substrate, prebaking usually at from 70 to 160° C. forfrom 1 to 10 minutes, irradiating (exposing) radiations via a prescribedmask, then carrying out post-exposure baking at from 70 to 160° C. for 1to 5 minutes to form a latent resist pattern, and subsequentlydeveloping with a developing solution.

For the exposure, radiations having various wavelengths, for example,ultraviolet rays, X-rays, and the like can be utilized. In general,excimer lasers such as g-rays, i-rays, XeCl, KrF, KrCl, ArF, ArCl, andthe like are used for semiconductor resists. Of these, from theviewpoint of refinement, it is preferable to use an ArF excimer laser.

An exposure dose is preferably from 0.1 to 1,000 mJ/cm², and morepreferably from 1 to 500 mJ/cm².

Examples of the developing solution include an alkaline aqueous solutionin which an inorganic base such as sodium hydroxide, potassiumhydroxide, sodium carbonate, ammonia water, and the like; an alkylaminesuch as ethylamine, diethylamine, triethylamine, and the like; analcoholamine such as dimethylethanolamine, triethanolamine, and thelike; a quaternary ammonium salt such as tetramethylammonium hydroxide,tetraethylammonium hydroxide, and the like; or the like is dissolved;and so on. Of these, it is preferable to use an alkaline aqueoussolution in which a quaternary ammonium salt such as tetramethylammoniumhydroxide, tetraethylammonium hydroxide, and the like is dissolved.

In general, a concentration of the developing solution is preferablyfrom 0.1 to 20% by mass, and more preferably from 0.1 to 10% by mass.

EXAMPLES

The present invention is hereunder described in more detail withreference to the Examples, but it should be construed that the presentinvention is not limited thereto at all. Incidentally, a measurementmethod of Mw and Mn and a calculation method of a degree of dispersionin each of the Examples are as follows.

(Measurement of Mw and Mn and Calculation of Degree of Dispersion)

A weight average molecular weight (Mw) and a number average molecularweight (Mn) were determined as reduced values according to calibrationcurves prepared with standard polystyrene by carrying out gel permeationchromatography (GPC) measurement using a differential refractometer as adetector and using tetrahydrofuran (THF) as an eluent under thefollowing condition. Also, a degree of dispersion (Mw/Mn) was determinedby dividing the weight average molecular weight (Mw) by the numberaverage molecular weight (Mn).

GPC measurement: A column obtained by connecting three of “TSK-gelsupermultipore HZ-M” (a trade name, manufactured by Tosoh Corporation,4.6 mm×150 mm) to each other in series was used, and the measurement wascarried out under a condition at a column temperature of 40° C., adifferential refractometer temperature of 40° C. and a flow rate of theeluent of 0.35 mL/min.

Also, the measurement of a film dissolution minimum exposure dose of thephotoresist composition obtained in each of the Examples was carried outin the following manner.

(Measurement of Film Dissolution Minimum Exposure Dose)

The photoresist composition obtained in each of the Examples was coatedon a silicon wafer having a diameter of 10 cm by a spin coating methodand prebaked on a hot plate at 130° C. for 90 seconds, thereby forming aresist film having a film thickness of 100 nm.

An ArF excimer laser having a wavelength of 193 nm was exposed on theobtained resist film through a slit of 1 mm×5 mm, while changingstepwise the exposure dose. After the exposure, post-exposure baking wascarried out on a hot plate at a temperature shown in FIG. 1 for 90seconds, and thereafter, the resultant was developed with a 2.38% bymass tetramethylammonium hydroxide aqueous solution for 90 seconds.

The wafer after the development was visually observed, therebydetermining a minimum exposure dose at which the resist caused filmdissolution (an exposure dose at which 80% or more of an exposed areawas dissolved was defined as a minimum exposure dose).

Synthesis Example 1 Synthesis of 6-azabicyclo[3.2.0]heptan-7-one

In a four-necked flask with a volume of 1 L, which was equipped with adropping funnel, a thermometer, and a nitrogen introducing tube, 150 g(2.2 mol) of cyclopentene and 450 g of toluene were charged, and 311 g(2.2 mol) of chlorosulfonyl isocyanate was added dropwise at 20° C.After completion of the dropwise addition, the mixture was furtherstirred at 30° C. for 48 hours.

The obtained reaction mixture was added dropwise to 1,300 g of a 20%sodium sulfite aqueous solution and hydrolyzed, and thereafter, theresultant was separated into an organic layer and an aqueous layer. Theaqueous layer was extracted twice with 1,000 g of ethyl acetate. Theorganic layer and the extract were mixed and concentrated under reducedpressure, thereby obtaining 210 g (1.9 mol) of6-azabicyclo[3.2.0]heptan-7-one having the following properties.

¹H-NMR (300 MHz, CDCl₃, ppm, TMS) δ: 1.32-2.09 (6H, m, CH₂×3), 3.49-3.54(1H, m, CH), 4.04-4.08 (1H, m, CH), 5.52 (1H, bs, NH)

Example 1 Synthesis of 6-methacryloyl-6-azabicyclo[3.2.0]heptan-7-one

In a three-necked flask with a volume of 50 mL, which was equipped witha dropping funnel, a thermometer, and a nitrogen introducing tube, 2 g(18 mmol) of 6-azabicyclo[3.2.0]heptan-7-one obtained in SynthesisExample 1, 2.7 g (27 mmol) of triethylamine, 0.22 g (1.8 mmol) of4-(N,N-dimethylamino)pyridine, and 6 g of methylene chloride werecharged. To this mixed solution, 2.3 g (20 mmol) of methacryloylchloride was added at 20° C., and the mixture was stirred at roomtemperature for 2 hours.

7 g of water was added dropwise to the obtained reaction mixture,thereby separating it into an organic layer and an aqueous layer. Theaqueous layer was extracted twice with 7 g of methylene chloride. Theorganic layer and the extract were mixed and concentrated under reducedpressure. The concentrate was purified by means of silica gel columnchromatography, thereby obtaining 2.6 g (14.4 mmol) of6-methacryloyl-6-azabicyclo[3.2.0]heptan-7-one having the followingproperties.

¹H-NMR (300 MHz, CDCl₃, ppm, TMS) δ: 1.48-2.35 (6H, m, CH₂×3), 2.00 (3H,s, CH₃), 3.53 (1H, m, CH), 4.50 (1H, m, CH), 5.75 (1H, m, CH₂), 6.00(1H, s, CH₂)

Synthesis Example 2 Synthesis of9-azatetracyclo[5.4.1.0^(2.6).0^(8.11)]undecan-10-one

In a four-necked flask with a volume of 1 L, which was equipped with adropping funnel, a thermometer, and a nitrogen introducing tube, 2.9 g(22 mmol) of dicyclopentadiene and 5 g of toluene were charged, and 3.1g (22 mmol) of chlorosulfonyl isocyanate was added dropwise at 20° C.After completion of the dropwise addition, the mixture was furtherstirred at 30° C. for 16 hours. The obtained reaction mixture was addeddropwise to 13 g of a 20% sodium sulfite aqueous solution andhydrolyzed, and thereafter, the resultant was separated into an organiclayer and an aqueous layer. The aqueous layer was extracted twice with10 g of toluene. The organic layer and the extract were mixed to obtaina reaction intermediate-containing toluene solution. The toluenesolution was transferred into an autoclave having a volume of 200 mL, towhich was then added 0.2 g of 10% by mass-palladium carbon, and themixture was then stirred under a condition at an internal temperature of60° C. and a hydrogen pressure of 0.5 MPa for 6 hours. After theinternal temperature was cooled to 25° C., the palladium carbon wasfiltered off, and the filtrate was concentrated under reduced pressure,thereby obtaining 3.2 g (18 mmol) of9-azatetracyclo[5.4.1.0^(2.6).0^(8.11)]undecan-10-one having thefollowing properties.

¹H-NMR (400 MHz, CDCl₃, ppm, TMS) δ: 1.42-1.66 (7H, m), 1.79 (1H, d,J=10.8 Hz), 2.35 (2H, d, J=4.0 Hz), 2.43-2.48 (1H, m), 2.54-2.57 (1H,m), 3.24 (1H, dd, J=3.2, 1.6 Hz), 3.62 (1H, d, J=3.6 Hz), 5.79 (1H, br)

Example 2 Synthesis of 9-methacryloyl-9-azatetracyclo[5.4.1.0^(2.6).0^(8.11)]undecan-10-o ne

The same procedure as those in Example 1 were followed, except for using3.2 g (18 mmol) of 9-azatetracyclo[5.4.1.0^(2.6).0^(8.11)]undecan-10-oneobtained in Synthesis Example 2 in place of6-azabicyclo[3.2.0]heptan-7-one, thereby obtaining 3.2 g (13 mmol) of9-methacryloyl-9-azatetracyclo[5.4.1.0^(2.6).0^(8.11)]undecan-10-o nehaving the following properties.

¹H-NMR (400 MHz, CDCl₃, ppm, TMS) δ: 1.42-1.57 (5H, m), 1.63-1.70 (3H,m), 1.98 (3H, s), 2.46 (1H, d, J=4.4 Hz), 2.52 (1H, m), 2.59 (1H, m),2.79 (1H, d, J=4.4 Hz), 3.23 (1H, d, J=4.4 Hz), 4.10 (1H, d, J=4.4 Hz),5.72 (1H, m), 5.98 (1H, s)

Synthesis Example 3 Synthesis of6-chloroacetyl-6-azabicyclo[3.2.0]heptan-7-one

In a four-necked flask with a volume of 300 mL, which was equipped witha thermometer, a stirrer, a dropping funnel, and a nitrogen introducingtube, 11.1 g (100 mmol) of 6-azabicyclo[3.2.0]heptan-7-one, 100 mL oftetrahydrofuran, and 12.1 g (120 mmol) of triethylamine were charged,and an internal temperature was cooled to 3° C. 12.4 g (110 mmol) of2-chloroacetyl chloride was added dropwise at that temperature over 15minutes from the dropping funnel. After completion of the dropwiseaddition, the mixture was stirred for 3 hours. Thereafter, 50 mL ofwater and 50 mL of ethyl acetate were added, and a liquid separationoperation was carried out. The obtained organic layer was concentratedunder reduced pressure, thereby obtaining 8.4 g (45 mmol) of6-chloroacetyl-6-azabicyclo[3.2.0]heptan-7-one having the followingproperties.

¹H-NMR (400 MHz, CDCl₃, ppm, TMS) δ: 1.46-1.68 (3H, m), 1.89-2.00 (1H,m), 2.10-2.19 (1H, m), 2.33 (1H, dd, J=14.2, 5.8 Hz), 3.60 (1H, dd,J=8.2, 4.6 Hz), 4.38 (1H, s), 4.40 (1H, s), 4.49 (1H, t, J=4.8 Hz)

Example 3 Synthesis of6-methacryloyloxyacetyl-6-azabicyclo[3.2.0]heptan-7-one

In a four-necked flask with a volume of 500 mL, which was equipped witha thermometer, a stirrer, a dropping funnel, and a nitrogen introducingtube, 9.7 g (70 mmol) of potassium carbonate, 0.7 g (4 mmol) ofpotassium iodide, 100 mL of dimethylformamide, 25.8 g (300 mmol) ofmethacrylic acid, and 18.8 g (100 mmol) of6-chloroacetyl-6-azabicyclo[3.2.0]heptan-7-one obtained in SynthesisExample 3 were charged, and the mixture was stirred at an internaltemperature of 25° C. for 5 hours. To the reaction mixture, 100 mL ofethyl acetate and 50 mL of water were added, and a liquid separationoperation was then carried out. The obtained organic layer wasconcentrated under reduced pressure and then purified by means of silicagel column chromatography, thereby obtaining 17.1 g (72 mmol) of6-methacryloyloxyacetyl-6-azabicyclo[3.2.0]heptan-7-one having thefollowing properties.

¹H-NMR (400 MHz, CDCl₃, ppm, TMS) δ: 1.48-1.67 (3H, m), 1.93 (1H, t,J=6.4 Hz), 1.99 (3H, s), 2.12 (1H, dd, J=12.4, 4.6 Hz), 2.33 (1H, dd,J=14.2, 5.4 Hz), 3.59 (1H, dd, J=8.0, 4.4 Hz), 4.46 (1H, t, J=4.6 Hz),5.00 (2H, s), 5.66 (1H, m), 6.22 (1H, m)

Synthesis Example 4 Synthesis ofspiro[azetidin-2-one-2,2′-3′,3′-dimethylbicyclo[2.2.1]hept ane]

In a four-necked flask with a volume of 1 L, which was equipped with adropping funnel, a thermometer, and a nitrogen introducing tube, 299.7 g(2.2 mol) of camphene and 450 g of toluene were charged, and 311 g (2.2mol) of chlorosulfonyl isocyanate was added dropwise at 20° C. Aftercompletion of the dropwise addition, the mixture was further stirred at30° C. for 48 hours.

The obtained reaction mixture was added dropwise to 1,300 g of a 20%sodium sulfite aqueous solution and hydrolyzed, and thereafter, theresultant was separated into an organic layer and an aqueous layer. Theaqueous layer was extracted twice with 1,000 g of ethyl acetate. Theorganic layer and the extract were mixed and concentrated under reducedpressure, thereby obtaining 304.7 g (1.7 mol) ofspiro[azetidin-2-one-2,2′-3′,3′-dimethylbicyclo[2.2.1]hept ane] havingthe following properties.

¹H-NMR (400 MHz, CDCl₃, ppm, TMS) δ: 0.91 (3H, s), 1.00 (3H, s),1.20-1.33 (2H, m), 1.63 (1H, dd, J=12.2, 8.4 Hz), 1.82-1.88 (3H, m),1.94-1.99 (1H, m), 2.10 (1H, d, J=17.2 Hz), 2.25 (1H, d, J=17.2 Hz),3.49 (1H, dd, J=8.2, 4.6 Hz), 6.4 (1H, br)

Example 4 Synthesis ofspiro[1-methacryloylazetidin-2-one-2,2′-3′,3′-dimethylbicyclo[2.2.1]heptane]

In a three-necked flask with a volume of 50 mL, which was equipped witha dropping funnel, a thermometer, and a nitrogen introducing tube, 3.2 g(18 mmol) of spiro[azetidin-2-one-2,2′-3′,3′-dimethylbicyclo[2.2.1]heptane] obtained in Synthesis Example 4, 2.7 g (27 mmol) of triethylamine,0.22 g (1.8 mmol) of 4-(N,N-dimethylamino)pyridine, and 6 g of methylenechloride were charged. To this mixed solution, 2.3 g (20 mmol) ofmethacryloyl chloride was added at 20° C., and the mixture was stirredat room temperature for 2 hours.

7 g of water was added dropwise to the obtained reaction mixture,thereby separating it into an organic layer and an aqueous layer. Theaqueous layer was extracted twice with 7 g of methylene chloride. Theorganic layer and the extract were mixed and concentrated under reducedpressure. The concentrate was purified by means of silica gel columnchromatography, thereby obtaining 3.3 g (13.7 mmol) ofspiro[1-methacryloylazetidin-2-one-2,2′-3′,3′-dimethylbicyclo[2.2.1]heptane] having the following properties.

¹H-NMR (400 MHz, CDCl₃, ppm, TMS) δ: 0.95 (3H, s), 0.99 (3H, s),1.30-1.37 (2H, m), 1.85-1.92 (3H, m), 1.94-1.98 (2H, m), 1.97 (3H, s),2.37 (1H, d, J=18.4 Hz), 2.46 (1H, d, J=18.4 Hz), 3.89 (1H, dd, J=7.4,5.4 Hz), 5.35 (1H, s), 5.39 (1H, s)

Synthesis Example 5 Synthesis of 3-acetoxyazetidinone

In a four-necked flask with a volume of 1 L, which was equipped with adropping funnel, a thermometer, and a nitrogen introducing tube, 189.4 g(2.2 mol) of vinyl acetate was charged, and 56.6 g (0.4 mol) ofchlorosulfonyl isocyanate was added dropwise at 3° C. After completionof the dropwise addition, the mixture was further stirred at 3° C. for48 hours.

The obtained reaction mixture was added dropwise to 174 g of sodiumsulfite, 93 g of sodium hydrogencarbonate, and 1,500 g of water andhydrolyzed. The resultant was extracted three times with 500 g ofchloroform. The organic layer was concentrated under reduced pressure,thereby obtaining 127.8 g (1.0 mol) of 3-acetoxyazetidinone having thefollowing properties.

¹H-NMR (400 MHz, CDCl₃, ppm, TMS) δ: 2.11 (3H, s), 2.99 (1H, dd, J=15.4,1.2 Hz), 3.27 (1H, dd, J=15.4, 4.0 Hz), 5.84 (1H, dd, J=4.0, 1.2 Hz),7.20 (1H, br)

Example 5 Synthesis of N-methacryloyl-3-acetoxyazetidinone

In a three-necked flask with a volume of 50 mL, which was equipped witha dropping funnel, a thermometer, and a nitrogen introducing tube, 2.3 g(18 mmol) of 3-acetoxyazetidinone obtained in Synthesis Example 5, 2.7 g(27 mmol) of triethylamine, 0.22 g (1.8 mmol) of4-(N,N-dimethylamino)pyridine, and 6 g of methylene chloride werecharged. To this mixed solution, 2.3 g (20 mmol) of methacryloylchloride was added at 20° C., and the mixture was stirred at roomtemperature for 2 hours.

7 g of water was added dropwise to the obtained reaction mixture,thereby separating it into an organic layer and an aqueous layer. Theaqueous layer was extracted twice with 7 g of methylene chloride. Theorganic layer and the extract were mixed and concentrated under reducedpressure. The concentrate was purified by means of silica gel columnchromatography, thereby obtaining 2.6 g (13.3 mmol) ofN-methacryloyl-3-acetoxyazetidinone having the following properties.

¹H-NMR (400 MHz, CDCl₃, ppm, TMS) δ: 2.00 (3H, s), 2.11 (3H, s), 2.99(1H, dd, J=15.4, 1.2 Hz), 3.77 (1H, dd, J=15.4, 4.0 Hz), 5.84 (1H, dd,J=4.0, 1.2 Hz), 5.75 (1H, m), 6.00 (1H, s)

Example 6 Synthesis of Polymer(A)

In a three-necked flask with an inner volume of 50 mL, which wasequipped with a magnetic stirrer, a reflux condenser, and a thermometer,5.51 g (23 mmol) of 2-methacryloyloxy-2-methyladamantane, 3.58 g (20mmol) of 6-methacryloyl-6-azabicyclo[3.2.0]heptan-7-one obtained inExample 1, and 36.4 g of methyl ethyl ketone were charged, and nitrogenbubbling was carried out for 10 minutes. 0.36 g (2 mmol) of2,2′-azobisisobutyronitrile was charged under a nitrogen atmosphere, andthe mixture was subjected to a polymerization reaction at 80° C. for 4hours.

The obtained reaction mixture was added dropwise to 220 g of methanol atroom, temperature while stirring, and a formed precipitate was collectedby filtration. The precipitate was dried under reduced pressure (26.7Pa) at 50° C. for 5 hours, thereby obtaining 7.3 g of Polymer (A)composed of the foregoing repeating units (the numerical values expressa molar ratio). The obtained Polymer (A) had a weight average molecularweight (Mw) of 8,000 and a degree of dispersion of 2.0.

Example 7 Synthesis of Polymer (B)

The same procedure as those in Example 6 were followed, except for using4.9 g (20 mmol) of9-methacryloyl-9-azatetracyclo[5.4.1.0^(2.6).0^(8.11)]undecan-10-o neobtained in Example 2 in place of 3.58 g (20 mmol) of6-methacryloyl-6-azabicyclo[3.2.0]heptan-7-one, thereby obtaining 7.2 gof Polymer (B) composed of the foregoing repeating units (the numericalvalues express a molar ratio). The obtained Polymer (B) had an Mw of8,500 and a degree of dispersion of 1.8.

Example 8 Synthesis of Polymer (C)

The same procedure as those in Example 6 were followed, except for using4.7 g (20 mmol) of6-methacryloyloxyacetyl-6-azabicyclo[3.2.0]heptan-7-one obtained inExample 3 in place of 3.6 g (20 mmol) of6-methacryloyl-6-azabicyclo[3.2.0]heptan-7-one, thereby obtaining 6.8 gof Polymer (C) composed of the foregoing repeating units (the numericalvalues express a molar ratio). The obtained Polymer (C) had an Mw of9,200 and a degree of dispersion of 1.7.

Example 9 Synthesis of Polymer (D)

The same procedure as those in Example 6 were followed, except for using4.95 g (20 mmol) ofspiro[1-methacryloylazetidin-2-one-2,2′-3′,3′-dimethylbicyclo[2.2.1]heptane] obtained in Example 4 in place of 3.6 g (20 mmol) of6-methacryloyl-6-azabicyclo[3.2.0]heptan-7-one, thereby obtaining 6.8 gof Polymer (D) composed of the foregoing repeating units (the numericalvalues express a molar ratio). The obtained Polymer (D) had a weightaverage molecular weight (Mw) of 8,500 and a degree of dispersion of2.0.

Example 10 Synthesis of Polymer (E)

The same procedure as those in Example 6 were followed, except for using3.9 g (20 mmol) of N-methacryloyl-3-acetoxyazetidinone obtained inExample 5 in place of 3.6 g (20 mmol) of6-methacryloyl-6-azabicyclo[3.2.0]heptan-7-one, thereby obtaining 5.4 gof Polymer (E) composed of the foregoing repeating units (the numericalvalues express a molar ratio). The obtained Polymer (E) had a weightaverage molecular weight (Mw) of 9,800 and a degree of dispersion of1.9.

Referential Example 1 Synthesis of Polymer (F)

The same procedure as those in Example 6 were followed, except for using5.11 g (23 mmol) of 5-methacryloyloxy-2,6-norbornane carbolactone inplace of 3.58 g (20 mmol) of6-methacryloyl-6-azabicyclo[3.2.0]heptan-7-one, thereby obtaining 6.3 gof Polymer (F) composed of the foregoing repeating units (the numericalvalues express a molar ratio). The obtained Polymer (F) had an Mw of11,800 and a degree of dispersion of 1.7.

Example 11 Photoresist Composition A

100 parts by mass of Polymer (A) obtained in Example 6, 4.5 parts bymass of TPS-09 (a trade name, manufactured by Midori Kagaku Co., Ltd.,component: triphenylsulfonium nonafluoro-n-butanesulfonate) as a photoacid generator, and 1,896 parts by mass of a propylene glycol monomethylether acetate/cyclohexanone mixed solvent (mass ratio: 1/1) as a solventwere mixed to obtain a solution in which the respective components wereuniform. Thereafter, the obtained solution was filtered with a membranefilter having a pore size of 0.2 μm, thereby obtaining PhotoresistComposition A (total solid content concentration: about 5% by mass).

By using the obtained Photoresist Composition A, a film dissolutionminimum exposure dose was measured according to the foregoing method.The results are shown in FIG. 1.

Example 12 Photoresist Composition B

The same procedure as those in Example 11 were followed, except forusing 100 parts by mass of Polymer (B) obtained in Example 7 in place of100 parts by mass of the Polymer (A), thereby obtaining PhotoresistComposition B. By using the obtained Photoresist Composition B, a filmdissolution minimum exposure dose was measured according to theforegoing method. The results are shown in FIG. 1.

Example 13 Photoresist Composition C

The same procedure as those in Example 11 were followed, except forusing 100 parts by mass of Polymer (C) obtained in Example 8 in place of100 parts by mass of the Polymer (A), thereby obtaining PhotoresistComposition C. By using the obtained Photoresist Composition C, a filmdissolution minimum exposure dose was measured according to theforegoing method. The results are shown in FIG. 1.

Example 14 Photoresist Composition D

The same procedure as those in Example 11 were followed, except forusing 100 parts by mass of Polymer (D) obtained in Example 9 in place of100 parts by mass of the Polymer (A), thereby obtaining PhotoresistComposition D. By using the obtained Photoresist Composition D, a filmdissolution minimum exposure dose was measured according to theforegoing method. The results are shown in FIG. 2.

Example 15 Photoresist Composition E

The same procedure as those in Example 11 were followed, except forusing 100 parts by mass of Polymer (E) obtained in Example 10 in placeof 100 parts by mass of the Polymer (A), thereby obtaining PhotoresistComposition E. By using the obtained Photoresist Composition E, a filmdissolution minimum exposure dose was measured according to theforegoing method. The results are shown in FIG. 3.

Comparative Example 1 Photoresist Composition F

The same procedure as those in Example 11 were followed, except forusing Polymer (F) in place of the Polymer (A), thereby obtainingPhotoresist Composition F. By using the obtained Photoresist CompositionF, a film dissolution minimum exposure dose was measured according tothe foregoing method. The results are shown in FIGS. 1 to 3,respectively.

It is noted from FIGS. 1 to 3 that as compared with PhotoresistComposition F, Photoresist Compositions A to E of the present inventioneach containing a polymer obtained using the N-acyl-β-lactam derivative(1) are very high in the post-exposure bake temperature at which thefilm dissolution exposure dose is lowered. Incidentally, it may be saidfrom FIG. 1 that among Photoresist Compositions A to C, the aciddiffusion length becomes short in the order of C>A>B.

In Photoresist Compositions A to E, the structural unit which is derivedfrom an acid dissociable dissolution inhibiting group-containing acrylicester is common, and a generated acid dissociation reaction is the same;and therefore, it may be said that when the photoresist composition ofthe present invention containing a polymer having the constituent unit(1′) is used, the acid diffusion length becomes shortcharacteristically. When the acid diffusion length becomes short, LWRcan be improved; and therefore, it is noted that when the photoresistcomposition of the present invention is used, a resist pattern having ahigh resolution is formed.

INDUSTRIAL APPLICABILITY

The photoresist composition of the present invention is useful for themanufacture of semiconductors or printed wiring boards because LWR isimproved, and a resist pattern having a high resolution is formed.

1. An N-acyl-β-lactam derivative represented by formula (1):

wherein: R¹ represents a hydrogen atom, a methyl group, or atrifluoromethyl group; W represents an alkylene group having a carbonnumber of from 1 to 10 or a cycloalkylene group having a carbon numberof from 4 to 10; n represents 0 or 1; and each of R², R³, R⁴, and R⁵independently represents a hydrogen atom, an alkyl group having a carbonnumber of from 1 to 5, a cyclic hydrocarbon group having a carbon numberof from 3 to 10, or an acyloxy group having a carbon number of from 2 to6, provided that: 1) R² and R³, or R⁴ and R⁵, are optionally connectedto each other to form a substituted or unsubstituted ring 1) having aring forming atom number of from 3 to 10, said ring 1) optionallycomprising an oxygen atom; 2) R³ and R⁴ are optionally connected to eachother to form a substituted or unsubstituted ring 2) having a ringforming atom number of from 4 to 10, said ring 2) optionally comprisingan oxygen atom; and 3) all of R², R³, R⁴, and R⁵ are not a hydrogen atomat the same time.
 2. The N-acyl-β-lactam derivative of claim 1, which isrepresented by formula (1-1):

wherein: R′ represents a hydrogen atom, a methyl group, or atrifluoromethyl group; each of R² and R⁵ independently represents ahydrogen atom or an alkyl group having a carbon number of from 1 to 5; Wrepresents an alkylene group having a carbon number of from 1 to 10 or acycloalkylene group having a carbon number of from 4 to 10; n represents0 or 1; and Z¹ represents a ring formed together with the two carbonatoms on the β-lactam, with a number of atoms forming the ring beingfrom 3 to
 10. 3. The N-acyl-β-lactam derivative of claim 1, which isrepresented by formula (1-2):

wherein: R¹ represents a hydrogen atom, a methyl group, or atrifluoromethyl group; each of R⁴ and R⁵ independently represents ahydrogen atom or an alkyl group having a carbon number of from 1 to 5; Wrepresents an alkylene group having a carbon number of from 1 to 10 or acycloalkylene group having a carbon number of from 4 to 10; n represents0 or 1; and Z² represents an aliphatic ring formed together with thecarbon atom on the β-lactam, with a carbon number forming the aliphaticring being from 3 to
 10. 4. The N-acyl-β-lactam derivative of claim 1,which is represented by formula (1-3):

wherein: R¹ represents a hydrogen atom, a methyl group, or atrifluoromethyl group; each of R⁴ and R⁵ independently represents ahydrogen atom or an alkyl group having a carbon number of from 1 to 5; Wrepresents an alkylene group having a carbon number of from 1 to 10 or acycloalkylene group having a carbon number of from 4 to 10; n represents0 or 1; and R^(A) represents an alkyl group having a carbon number offrom 1 to 5 or a cyclic hydrocarbon group having a carbon number of from3 to
 10. 5. A polymer obtained by polymerizing the N-acyl-β-lactamderivative of claim
 1. 6. A photoresist composition, comprising thepolymer of claim 5, a photo acid generator, and a solvent.
 7. A polymerobtained by polymerizing the N-acyl-β-lactam derivative of claim
 2. 8. Apolymer obtained by polymerizing the N-acyl-β-lactam derivative of claim3.
 9. A polymer obtained by polymerizing the N-acyl-β-lactam derivativeof claim
 4. 10. A photoresist composition, comprising the polymer ofclaim 7, a photo acid generator, and a solvent.
 11. A photoresistcomposition, comprising the polymer of claim 8, a photo acid generator,and a solvent.
 12. A photoresist composition, comprising the polymer ofclaim 9, a photo acid generator, and a solvent.